Currently, the predominant packaging approach is two dimensional wherein components are placed on a carrier and electrical intercommunication occurs only in the X-Y plane. A common example of this may be found in the conventional tape automated bonding or "TAB" type packaging systems well known in the art.
While such TAB packaging illustrates the evolution of electronic packaging art into increasingly higher density packages, practical limits to the degree of miniaturization possible in the X-Y plane arose thereby constraining improvements in packaging density. This was due, for example, to finite limitations which could practically be achieved in conductive line pitches which could be etched or otherwise established on planar substrates. Moreover, and perhaps more problematical, was the fact that many components often needed to be located proximally to one-another, which is an inherent limitation of X-Y planar component positioning.
Accordingly, with manufacturing and packaging technology reaching practical limits in one plane, attention began to focus in the development of the art on ways to increase density through use of the vertical or Z axis direction. Thus, these considerations gave rise to numerous elaborate schemes for providing vertical "sandwiches" of components, circuits and even stacked pluralities of electrically interconnected horizontal boards. However, several problems were associated with these attempts to extend the packaging art.
First, by providing multi-layered packaging, thermal management problems surfaced which were destructive of the circuits being vertically stacked upon one another. Heat generated by a given package would naturally rise thereby affecting adjacent packages attempting to stack multiple packages vertically, the problem of thermal destruction was compounded.
Moreover, as may be seen by review of illustrative attempts to capitalize on space available in the Z axis direction, elaborate, expensive and often unreliable interconnecting schemes, including mechanical connectors and the like, were devised for effecting vertical conductive paths as required and desired. Not only were these connecting schemes unreliable, but often they created extremely difficult problems in terms of manufacturing and assembly.
For these and other reasons, a modular packaging system was highly desired which was simple to construct, provided extremely high-density interconnect capability, was flexible in terms of varying degrees of package density which could be accommodated, avoided the necessity for complicated mechanical interconnections, and, at the same time, provided a solution to the aforementioned thermal management problems. These and other benefits of the present invention are provided.